GlobalMass team member Bramha Dutt Vishwakarma is the lead author on a new paper published in Remote Sensing (‘What Is the Spatial Resolution of GRACE Satellite Products for Hydrology?‘).
The starting point for the paper is a simple question: What is the minimum catchment size that can be efficiently monitored using the GRACE satellite products? Although we know the theoretical spatial resolution of the ‘raw’ GRACE data, the effect of post-processing means that, in practice, GRACE products have a coarser spatial resolution. However, with studies focusing on different catchments and advances in post-processing strategies, multiple estimates of the effective spatial resolution have been produced.
This new paper provides a comprehensive study of GRACE products in order to evaluate the practical spatial resolution. Bramha and his colleagues looked at GRACE data across 255 catchments globally to assess the general behaviour of error with respect to catchment size. They found that error increases as the catchment size decreases, but that the rate at which it increases depends on the post-processing method used. They concluded that, using the method found to produce the lowest error (the data-driven approach), a catchment of approximately 63,000 sq. km area can be monitored with an RMS error of 2 cm, which is one third of the minimum catchment size assumed in previous studies using other post-processing methods.
Reference: Vishwakarma, B.D.; Devaraju, B.; Sneeuw, N. What Is the Spatial Resolution of grace Satellite Products for Hydrology? Remote Sens. 2018, 10, 852. DOI:10.3390/rs10060852